Louise Knight is pregnant but loses her child in a car crash. Blaming herself, she cannot forget the child that she would have called Toby. When she becomes pregnant again, she cannot persuade her husband or her doctors that she is haunted by the malevolent spirit of Toby—who threatens her life and that of her unborn child.
A couple move into Windwhistle House, a Victorian mansion in Yorkshire. After a sequence of horrific incidents, the woman becomes convinced that the house is haunted but her husband, who has made a successful career debunking the paranormal, is sceptical. When she hears a rumour that the previous owner murdered his wife, she leaves, and her husband is left to discover his home's secrets alone....
In a small Yorkshire town, Detective Inspector Jack Taylor tries desperately to find the child murderer who strikes when it is full moon. After five murders, the town dreads number six. A psychiatrist examines the drawings of local school children and discovers an important clue. When Taylor uncovers a connection to an ancient Druidic site and thinks he has discovered the murderer's identity, he realises that the next victim-to-be is his own son.